Klebsiella pneumoniae is a common pathogen of nosocomial pneumonia worldwide and community-acquired pneumonia (CAP) in Asia. Previous studies have shown that K. pneumoniae bacteremic CAP is associated with high mortality. We aimed to revisit K. pneumoniae bacteremic pneumonia in the current era and determine the risk factors associated with 28-day mortality. Between January 2014 and August 2020, adult patients with K. pneumoniae bacteremic pneumonia in a medical center in Taiwan were identified. Clinical and microbiological characteristics were compared between CAP and nosocomial pneumonia. Risk factors for 28-day mortality were analyzed using multivariate logistic regression. Among 150 patients with K. pneumoniae bacteremic pneumonia, 52 had CAP and 98 had nosocomial pneumonia. The 28-day mortality was 52% for all patients, 36.5% for CAP, and 60.2% for nosocomial pneumonia. Hypervirulent K. pneumoniae was more prevalent in CAP (61.5%) than in nosocomial pneumonia (16.3%). Carbapenem-resistant K. pneumoniae was more prevalent in nosocomial pneumonia (58.2%) than in CAP (5.8%). Nosocomial pneumonia, a higher Severe Organ Failure Assessment score, and not receiving appropriate definitive therapy were independent risk factors for 28-day mortality. In conclusion, revisiting K. pneumoniae bacteremic pneumonia in the current era showed a high mortality rate. Host factors, disease severity, and timely effective therapy affect the treatment outcomes of these patients.
Treatment of carbapenem-resistant
Klebsiella pneumoniae
(CRKP) infections is challenging due to the limited options of antibiotics. Colistin is one of the last-resort antibiotics if novel antimicrobial agents are not available.
We set out to study the prevalence of the mcr-1 gene in carbapenemase-producing Klebsiella pneumoniae (CPKP) strains, and to determine whether its presence is associated with a fitness cost. A total of 234 clinical CPKP isolates were collected from a tertiary medical center in Taiwan from January 2018 to January 2019. The mcr-1 and carbapenemase genes were detected by polymerase chain reaction (PCR) followed by Sanger sequencing. The mcr-1-positive carbapenemase-producing strain was characterized by whole genome sequencing, a plasmid stability test and a conjugation assay. In vitro growth rate and an in vivo virulence test were compared between the parental mcr-1-positive strain and its mcr-1 plasmid-cured strain. We identified only one mcr-1 positive strain (KP2509), co-harboring blaKPC–2 and blaOXA–48, among 234 (1/234, 0.43%) CPKP strains. KP2509 and its Escherichia coli mcr-1 transconjugant showed moderate colistin resistance (MIC = 8 mg/L). The mcr-1 is located on a large conjugative plasmid (317 kb), pKP2509-MCR, with three replicons, IncHI, IncFIB, and IncN. Interestingly, a complete Type IV-A3 CRISPR-Cas system was identified in pKP2509-MCR. Plasmid pKP2509-MCR was highly stable in KP2509 after 270 generation of passage, and the pKP2509-MCR cured strain PC-KP2509 showed similar growth rate and in vivo virulence in comparison to KP2509. The prevalence of mcr-1 in CPKP strains remains low in our center. Notably, we identified a large plasmid with multiple replicons containing both the mcr-1 and the Type IV-3A CRISPR-Cas genes. The further spread of this highly stable plasmid raises concern that it may promote the increase of mcr-1 prevalence in CPKP.
Background
Klebsiella pneumoniae liver abscess (KPLA) is an endemic disease in East Asia. KPLA is usually caused by hypervirulent strains that are susceptible to all kinds of antibiotics except ampicillin. Patients with KPLA are commonly treated with β-lactams and need prolonged duration of intravenous therapy. Fluoroquinolone has high oral bioavailability and has the potential to shorten the duration of intravenous therapy, but studies regarding fluoroquinolone use in KPLA are limited. We aimed to compare the outcomes of patients with KPLA treated with β-lactams and fluoroquinolone.MethodsConsecutive patients with KPLA in a tertiary medical center of Taiwan between 2011 and 2018 were enrolled retrospectively. Clinical characteristics and treatment outcomes were compared between cases treated with β-lactams and fluoroquinolones. Logistic regression was performed to identify risk factors of prolonged hospitalization (defined as > 30 days). Capsular genotypes and presence of rmpA or rmpA2 genes were analyzed among K. pneumoniae strains collected after July 2012. Hypervirulent strains were defined as those had rmpA or rmpA2 genes.ResultsA total of 330 KPLA patients identified, and the in-hospital mortality was 0.9% (n = 3). Nearly all K. pneumoniae strains were hypervirulent strains (97.1%). Capsular type K1 (n = 176) and K2 (n = 63) were the most common capsular types. Most patients received β-lactams (n = 296, 89.7%), and only 34 (10.3%) patients received fluoroquinolones as the main antibiotics (levofloxacin = 17; moxifloxacin = 10; ciprofloxacin = 7). The duration of intravenous antibiotics use in fluoroquinolones group was shorter than β-lactams group (20.12 ± 9.21 vs. 26.81 ± 16.10, P = 0.001). Prolonged hospitalization was more common in β-lactams group than fluoroquinolones group (32.1% vs. 11.8%, P = 0.014). The in-hospital mortality, duration of antibiotic use, and recurrence rate were similar between the two groups. Fluoroquinolones was independent protective factor for prolonged hospitalization (hazard ratio, 0.28; P = 0.026).ConclusionFluoroquinolone is able to shorten the duration of intravenous antibiotic use and beneficial in prolonged hospitalization in patients with KPLA.Disclosures
All authors: No reported disclosures.
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